Southern Gaza girds for the war’s next phase.

About 1.8 million Gazans have already been displaced by the war, according to the United Nations, and many say there is nowhere left for them to seek refuge.

Israel’s defense minister, Yoav Gallant, posted a photograph on social media of himself in an Israeli attack helicopter, saying he had watched some of Friday’s strikes on Gaza from the air.

“This morning we returned to hitting Hamas with full force,” he wrote on the social media platform X. “Hamas only understands force.”

The weeklong pause in fighting was an opportunity for hundreds of aid trucks to enter Gaza, carrying supplies of food, water, medicine and some fuel, although aid groups said the relief was still far short of what was needed.

On Friday, those shipments were initially halted after the cease-fire collapse, but Israel’s agency overseeing policy for the Palestinian territories said later in the day that “tens” of aid trucks had been allowed in.

John F. Kirby, a spokesman for the National Security Council, said Israel, at the United States’ urging, had agreed on Friday to allow a reduced number of aid trucks to continue entering Gaza.

“Probably in terms of dozens of trucks versus hundreds of trucks,” he said at a news briefing.

Martin Griffiths, the U.N.’s chief official for humanitarian and relief affairs, called for a lasting humanitarian cease-fire, saying the level of destruction and death was “unacceptable.” The seven-day pause, he said, was a glimpse of what peace in Gaza could look like.

“While it barely scratched the surface of what people need, it still allowed aid agencies to provide some basic supplies, reach areas which have been cut off for weeks, and offer some respite to deeply traumatized families,” he said in a statement on Friday.

Iyad Abuheweila contributed reporting from Cairo, and Erica L. Green from Washington.